Multi-physical field simulation method and system for air gap TSV thermal stress

Abstract

The invention discloses a multi-physical field simulation method and system for air gap TSV thermal stress. The method comprises the steps that an air gap TSV geometric model is constructed, the material attributes of a single air gap TSV are set, the material attributes comprise the elastic modulus, the Poisson's ratio and the density, grid division is conducted on the air gap TSV geometric model, and ABAQUS software is used for conducting physical field simulation on the air gap TSV geometric model. According to the simulation system, the building module completes building of geometric simulation model components, the parameter setting module rapidly adds material attributes needed by experiments, the assembly setting module completes combination of geometric components, the analysis step module adds types used for analyzing the models, and the interaction module can completely restrain the simulation model. And finally, solving through the simulation module to obtain a required result. The device can challenge different temperatures and different load cycle impacts at any time, facilitates the finding of the critical destructive power of a product, is high in practicality, can effectively reduce the thermal stress of an air gap TSV, and achieves the high density and high integration performance of an electronic device.

Description

TECHNICAL FIELD

[0001] The present application relates to SiP (system in package) simulation technology, in particular to a kind of air gap TSV thermal stress multi-physics field simulation method and system. BACKGROUND

[0002] Electronic components are developing and gradually fine, miniaturization, but the life of electronic components is extremely fragile, temperature expansion in handling use process leads to life shortening factor, and the highly integrated package of today such as 3D package or 2.5D package, cumulative addition of chip in Z axis direction, signal example improves while the heat emitted also sharply increases, the heat dissipation is too poor through heat convection transmission effect, and the heat generated by chip is transmitted to lower level by through silicon via (TSV), and heat dissipation is accelerated.

[0003] The emergence of new generation of electronic components such as the most advanced SiP (system in package), the packaging of chip is towards 2.5D / 3D package, the connection between electronic components is more precise and thin, while the power of electronic components is greatly increased, and the heat emitted is sharply increased.

[0004] At present, electronic components have more experimental and simulation researches on traditional TSV, from changing the aspect ratio of TSV to changing its material properties, and considering the elastic-plasticity and anisotropy of silicon substrate. But the traditional TSV technology directly contacts copper column with silicon substrate / oxide layer, which will be directly extruded when the device is heated and expanded, resulting in KOZ (exclusion zone) around TSV, affecting the embedding of electronic components and reducing the effective use area of silicon chip. If the contact between copper column and silicon substrate can be avoided during heating and expansion, the KOZ will be greatly reduced, and the effective use area of silicon chip will be improved. However, for this problem, the existing technology only studies the electrical signal of TSV, and adds a certain air between electronic components and silicon chip to achieve insulation effect, but ignores the most important thermal structure influencing factor. SUMMARY

[0005] In view of the problems in the background art, the present application provides a kind of air gap TSV thermal stress multi-physics field simulation method and system, overcome the simulation method of air gap TSV thermal stress, see the effect of new TSV on thermal stress well. Find the critical failure of product, effectively reduce thermal stress, and better optimize product design.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows. A kind of air gap TSV thermal stress multi-physics field simulation method, its steps are as follows: 1) Constructing a geometric model of air-gap TSV, a copper column is arranged at the center of a cuboid silicon substrate, the copper column is wrapped with two layers of dielectric layers, a gap is arranged between the two layers of dielectric layers, and RDL aluminum sheets are arranged at both ends of the copper column, and a single air-gap TSV is analyzed through the RDL aluminum sheets; 2) Setting the material properties of the single air-gap TSV, including elastic modulus, Poisson's ratio and density, wherein the copper column is copper, the silicon substrate is isotropic silicon, the dielectric layer is silicon dioxide (SiO2), and the RDL layer is an aluminum sheet; 3) Adding an analysis step setting to the air-gap TSV geometric model, the analysis time is 1800 seconds, and the model is assembled and constrained; 4) Setting the boundary conditions of the air-gap TSV geometric model, setting the physical field, wherein the temperature interval is set as an amplitude curve, the contact behavior is set as surface contact, the mechanical option is set as tangential behavior without friction, and the normal behavior is set as hard contact; the heat conduction mode is adopted, and a gap is arranged in the middle of the gap model to add the influence factor of thermal radiation; at the same time, a center axis is arranged at the center of the geometric model, and the thermal effect of the copper column at the operating temperature is simulated by center axis constraint; 5) The air-gap TSV geometric model is meshed, and the mesh of the copper column and the dielectric layer is subdivided, and the mesh of the silicon substrate and the dielectric layer is roughly divided to save calculation time; 6) According to the simulation conditions set by the above steps, the physical field simulation of the air-gap TSV geometric model is carried out by using ABAQUS software, and the simulation result is obtained.

[0007] Further, the copper column is a cylindrical shape.

[0008] Further, the subdivision refers to dividing the grid cell size side length to be less than 0.1 μm, and using sweep mesh division, the copper column is divided into four equal parts in the axial direction.

[0009] Further, the rough division refers to dividing the cell size side length to be greater than 0.1 μm to save calculation resources.

[0010] A multi-physical field simulation system for air-gap TSV thermal stress, comprising: A construction module for constructing an air-gap TSV geometric model and determining geometric parameters; A parameter setting module for setting various material parameters of the geometric model; An assembly setting module for assembling and constraining the geometric model; An analysis step module for adding an analysis step setting and setting the analysis step time; An interaction module for setting the contact mode of the geometric model and the surface mutual properties; Load setting module: used for setting boundary conditions, load and pre-defined field of the geometric model in simulation state; Simulation module: used for physical field simulation of the set conditions, and obtaining simulation results; The geometric simulation model component is established through the construction module, the material properties required by the experiment are quickly added through the parameter setting module, the combination of geometric components is completed through the assembly setting module, the type used for analyzing the model is added through the analysis step module, the constraint of the simulation model is completely realized through the interaction module, the result is ensured to be accurate, and finally the required result is obtained through the simulation module.

[0011] The present application simulates the multi-physical field of the air gap TSV thermal stress, simulates various geometric parameters, various material parameters and physical parameters, and boundary conditions and interaction forces, obtains stress strain and deformation displacement results, and uses the simulation results to guide product optimization design and field production, so that the optimization key parts are strengthened. Different temperature and different load cycle impact can be challenged at any time, and the critical breaking force of the product can be easily found, which is used to guide the optimization generation. The practicability is strong, the thermal stress of the air gap TSV can be effectively reduced, the high-density and high-integration performance of the electronic component are realized, and the present application can be widely applied in the industry. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a method flowchart of the present application; Figure 2 is a whole three-dimensional model diagram of the present application; Figure 3 is Figure 2 is an enlarged structure schematic view of A in the present application; Figure 4 is a load constraint structure diagram of the copper column 4 and the RDL aluminum sheet 2 in the present application; Figure 5 is a mesh division schematic view in the present application; Figure 6 is an average whole stress diagram of the present application; Figure 7 is an enlarged stress nephogram of the key part in the present application; Figure 8 is a temperature nephogram of the present application; Figure 9 is a shear stress nephogram of the present application; Figure 10 is a thermal flux schematic nephogram of the present application.

[0013] In the figure: 1-silicon substrate, 2-RDL aluminum sheet, 3-dielectric layer, 4-copper column, 5-air gap. DETAILED DESCRIPTION

[0014] The application will be further described in conjunction with the drawings and specific embodiments, referring to Figures 1 to 10 The application can be better understood and implemented, but the embodiments are not as limitations of the application.

[0015] The application relates to a multi-physical field simulation method for air-gap TSV thermal stress (as shown in Figure 1 The method comprises the following steps: Step S1: constructing an air-gap TSV geometric model 101 and determining various geometric parameters of the air-gap TSV geometric model, wherein the air-gap TSV geometric model is a single model; Step S2: setting various material parameters of the air-gap TSV model 102; Step S3: adding the setting of an analysis step 103 to the air-gap TSV model, and assembling the model; Step S4: setting the boundary conditions 104 of the air-gap TSV geometric model, setting the physical field, and interaction; Step S5: and meshing the air-gap TSV geometric model 105; Step S6: according to the various conditions set in steps S1 to S6, performing physical field simulation on the air-gap TSV model, and obtaining simulation results 106.

[0016] Embodiment The application performs physical field simulation on the air-gap TSV model, sets various geometric parameters, various material parameters and physical parameters of the air-gap TSV geometric model, load, thermal amplitude, boundary conditions, stress and heat transfer properties, obtains simulation results, and uses the simulation results to guide product optimization design and field production, so as to strengthen the optimization of key parts.

[0017] In step S1, the ABAQUS software (version 2020) is used to draw the air-gap TSV according to the size data of each part, and simulation is performed in the software after completion.

[0018] As shown in Figure 2 and 3 In step S1, the air-gap TSV geometric model of the embodiment is a assembled structure, which comprises a silicon substrate 1, a dielectric layer 3, a copper column 4, an RDL aluminum sheet 2 and an air gap 5 between the two dielectric layers 3. The air-gap TSV geometric model is constructed as a rectangular cuboid silicon substrate 1, and the center of the rectangular cuboid silicon substrate 1 is provided with the copper column 4, the outer periphery of the copper column 4 is wrapped with the two dielectric layers 3, the gap 5 is between the two dielectric layers 3, and the RDL aluminum sheet 2 is arranged at both ends of the copper column 4, so that the single air-gap TSV can be analyzed through the RDL aluminum sheet 2; the copper column in the air-gap TSV is 50 um high and 10.5 um in radius, and the air gap is 2.5 um.

[0019] In step S2, the air-gap TSV geometric model material is set, in which the silicon substrate 1 is set as isotropic silicon material, the dielectric layer 3 is set as silicon dioxide material, the copper column 4 is set as pure copper material, and the RDL aluminum sheet 2 is set as pure aluminum material. The values are assigned through the material property module of the ABAQUS software. The copper column 4 is located at the geometric center of the silicon substrate 1, that is, the silicon substrate 1 is a cube, the copper column 4 is wrapped by the silicon substrate 1, and the RDL aluminum sheet 2 is located at the two ends of the copper column 4, as shown in FIG. 2. Figures 2 to 4

[0020] The specific material parameters of the silicon substrate 1, the copper column 4, the RDL aluminum sheet 2, and the dielectric layer 3 in the embodiment are shown in Table 1.

[0021] In step S3, the analysis step is added to the air-gap TSV geometric model. In the analysis step setting, the analysis time is added, and the analysis step is set to 1800 seconds including temperature rise and fall. The geometric model is assembled.

[0022] For convenience of calculation and time saving, only a single modeling is performed on the air-gap TSV.

[0023] In step S4, surface constraints and loads must be applied to the package assembly during operation, and the interaction property is added.

[0024] The highest temperature of the air-gap TSV geometric model is set to 500°C, and the final temperature is set to 40°C.

[0025] The contact behavior of the air-gap TSV geometric model is set to surface contact, and the mechanical option is set to tangential behavior without friction and normal behavior as hard contact.

[0026] There is air in the air-gap TSV geometric model, and the influence factor of thermal radiation needs to be added.

[0027] The air-gap TSV geometric model is set with a center axis, and appropriate constraints are applied to simulate the thermal effect of the Cu column at the operating temperature.

[0028] In step S5, the mesh division of the air-gap TSV geometric model is set.

[0029] The structure of the air-gap TSV geometric model is complex, and therefore, in order to improve the operation efficiency and reduce the software running calculation time, the air-gap TSV geometric model is further divided into regions, and the copper column 4 and the dielectric layer 3 are mainly divided, and other parts are roughly divided. The specific mesh division effect is shown in FIG. 3. Figure 5

[0030] The other physical fields are kept as the software default settings.

[0031] ​​​In order to simulate the real situation of the air-gap TSV, the ambient temperature of 25 DEG C is added.

[0032] Step S6: According to the set conditions, the physical field simulation of the air-gap TSV geometric model is carried out, and the simulation result is obtained.

[0033] After all the settings are completed, the job module on the ABAQUS software is clicked, and the job is submitted, and the calculation result is waited. Figures 6 to 10 After the calculation is completed, the calculation result can be viewed by clicking the result, or directly clicking the visualization option.The final air-gap TSV thermal stress simulation result is shown in (1) The overall thermal stress distribution of the packaging assembly is calculated, as shown in Figure 6 It can be seen that the stress of the air-gap TSV decreases from the middle to the periphery.

[0034] (2) After calculation, the thermal stress nephogram of the key position can be clearly seen, as shown in Figure 7 It can be seen that the stress of the air-gap TSV is the largest at the contact between the middle copper column 4 and the dielectric layer 3.

[0035] (3) The air-gap TSV temperature distribution nephogram is calculated, and the temperature accumulates, and the heat dissipation is difficult, as shown in Figure 8

[0036] (4) The air-gap TSV shear stress nephogram is calculated, as shown in Figure 9 The maximum shear stress is 2.543 MPa.

[0037] (5) The air-gap TSV heat flux nephogram is calculated, as shown in Figure 10 The maximum heat flux is 0.7622.

[0038] The air-gap TSV thermal stress multi-physical field simulation system provided by the application comprises: The construction module is used for constructing the air-gap TSV geometric model and determining the geometric parameters of the air-gap TSV geometric model. The parameter setting module is used for setting the material parameters of the air-gap TSV geometric model. The assembly setting module is used for assembling and constraining the air-gap TSV geometric model. The analysis step module is used for setting the analysis step of the air-gap TSV geometric model. The interaction module is used for setting the contact mode, contact type and heat conduction mode of the air-gap TSV component geometric model. The load setting module is used for setting the boundary condition, load and predefined field of the air-gap TSV geometric model under simulation. Simulation module: used for physical field simulation of air-gap TSV geometric model according to set conditions, and simulation results are obtained.

[0039] The steps in the above example one can be quickly experimented through a systematic process, that is, the establishment of geometric simulation model components is completed through a construction module, material properties required by the experiment are quickly added through a parameter setting module, the combination of geometric components is completed through an assembly setting module, the type used for analyzing the model is added through an analysis step module, the constraint of the simulation model is completely realized through an interaction module, the accuracy of the result is ensured, and finally the required result is obtained through a simulation module.

[0040] Through the application, the thermal stress is reduced by 11% under the same conditions compared with the traditional TSV, the adverse effects of the thermal stress on electronic components can be effectively reduced, the yield of the device can be effectively controlled, and the product quality is improved.

Claims

1. A method for multi-physics simulation of air-gap TSV thermal stress, characterized in that, The steps are as follows: 1) Constructing a gas gap TSV geometric model, the center of the cuboid silicon substrate is provided with a copper column, the outer periphery of the copper column is wrapped with two layers of dielectric layers, the gap is between the two layers of dielectric layers, and RDL aluminum sheets are arranged at both ends of the copper column, and a single gas gap TSV is analyzed through the RDL aluminum sheets; 2) Setting the material properties of the single gas gap TSV include elastic modulus, Poisson's ratio and density, wherein: the copper column is copper, the silicon substrate is isotropic silicon, the dielectric layer is silicon dioxide, and the RDL layer is aluminum sheet; 3) Adding the setting of the analysis step to the gas gap TSV geometric model, the analysis time is 1800 seconds, and the model is assembled and constrained; 4) Setting the boundary conditions of the gas gap TSV geometric model, setting the physical field, wherein: the temperature interval is set as an amplitude curve, the contact behavior is set as surface contact, the mechanical option is set as tangential behavior without friction, and the normal behavior is set as hard contact; the heat conduction mode is adopted, and a gap is arranged in the middle of the gap model, so as to add the influence factor of thermal radiation; at the same time, a center axis is arranged at the center of the geometric model, and the thermal effect of the copper column under the operating temperature is simulated through the center axis constraint; 5) The gas gap TSV geometric model is meshed, the mesh of the copper column and the dielectric layer is subdivided, and the mesh of the silicon substrate and the dielectric layer is roughly divided, so as to save the calculation time; 6) According to the simulation conditions set by the above steps, the physical field simulation of the gas gap TSV geometric model is carried out by using ABAQUS software, and the simulation result is obtained.

2. The multi-physics simulation method of air-gap TSV thermal stress according to claim 1, wherein, The copper column is cylindrical.

3. The multi-physics simulation method of air-gap TSV thermal stress according to claim 1, wherein, The subdivision refers to dividing the grid cell size side length to be less than 0.1 μm, and using sweep mesh division, the copper column is cut into four equal parts in the axial direction.

4. The multi-physics simulation method of air-gap TSV thermal stress according to claim 1, wherein, The rough division refers to dividing the cell size side length to be greater than 0.1 μm, so as to save the calculation resources.

5. The multi-physics simulation system of air-gap TSV thermal stress according to claim 1, wherein, It comprises: A construction module for constructing a gas gap TSV geometric model and determining geometric parameters; A parameter setting module for setting various material parameters of the geometric model; An assembly setting module for assembling and constraining the geometric model; An analysis step module for setting the analysis step; An interaction module for setting the contact mode of the geometric model and the surface mutual properties; A load setting module for setting the boundary conditions, load and predefined field of the geometric model in the simulation state; A simulation module for physically simulating the set conditions and obtaining the simulation result; Through the construction module, the establishment of the geometric body simulation model part is completed, the parameter setting module quickly adds the material properties required by the experiment, the assembly setting module completes the combination of the geometric parts, the analysis step module adds the type for analyzing the model, the interaction module can completely constrain the simulation model, and the result is accurate. Finally, the required result is obtained by solving through the simulation module.

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